Altered Functional Connectivity of Hippocampal Subfields in Poststroke Dementia

Area of Science:

• Neuroimaging
• Cognitive Neuroscience
• Neurology

Background:

• The hippocampus (HP) is crucial for memory and spatial functions, with distinct longitudinal organization.
• Previous research noted volumetric atrophy in HP subfields in post-stroke dementia (PSD) patients.
• Altered functional connectivity (FC) in HP subfields in PSD remains poorly understood.

Purpose of the Study:

• To investigate functional connectivity (FC) alterations in hippocampus (HP) subfields in patients with post-stroke dementia (PSD).

Main Methods:

• Utilized 3.0T MRI, including resting-state functional and diffusion tensor imaging.
• Segmented HP subfields and analyzed directed functional connectivity (dFC) using Granger causality analysis.
• Compared dFCs between PSD patients, non-demented post-stroke (PSND) patients, and healthy controls.

Main Results:

• Identified functional divisions within the HP: HP head, body, and tail along the longitudinal axis.
• PSD patients showed reduced inward and increased outward information flow in the bilateral HP/HP head and left HP body.
• Cognitive scores correlated with dFCs in the bilateral HP and left HP head; dFCs improved PSD vs. PSND classification (94% accuracy).

Conclusions:

• Altered information transmission and reception within specific HP subfields characterize PSD.
• These functional connectivity changes offer insights into the neurophysiological underpinnings of PSD.
• HP subfield dFCs serve as potential biomarkers for differentiating PSD from non-demented post-stroke individuals.